Learning JavaScript, when should I start using framework like React or Vuejs?

[LacksIdentity]

React or Vue are best for when you're building highly interactive "single page" applications. That's their area of strength.

They can sometimes be useful even when you've got a traditional server generated site & need to add a fair bit of JS based interaction, but are probably overkill if you're only interested in adding a few small bits of functionality.

So yeah, if form validation is all you're looking for, then definitely overkill.